Quiet Breathing Research Articles

Effect of five different body positions on lung function in stroke patients with tracheotomy

ABSTRACT Background In stroke patients with tracheotomy, reduced lung function heightens pulmonary infection risk. Body position can affect lung function; however, its impact in stroke patients with tracheostomy remains unclear. Objective To investigate the influence of five body positions on pulmonary function in stroke patients with tracheotomy. Methods Pulmonary function was assessed in five body positions (supine, supine 30°, supine 60°, sitting, and prone) in 47 stroke patients who underwent tracheotomy. Diaphragmatic excursion during quiet breathing (DEQ), diaphragmatic thickening fraction during quiet breathing (DTFQ), and diaphragmatic excursion during coughing (DEC) were measured using ultrasound. Peak cough flow (PCF) was measured using an electronic peak flow meter. Results Different positions had a significant impact on DEQ, DEC, and PCF in stroke patients with tracheotomy, although not on DTFQ. DEQ showed no significant differences between supine 60°, sitting, and prone positions. Both DEC and PCF reached their maximum values in the sitting position. In the sub-group analysis, DEQ in females did not show significant differences across different positions. Both males and females exhibited significantly higher PCF in the sitting compared to supine position. The lung function of obese patients was significantly better in the sitting than in the supine and supine 30° position. Regardless of the patient’s level of consciousness and whether the brainstem was injured, lung function in the sitting position was significantly higher than in the supine position. Conclusions Body posture influences lung function in stroke patients with tracheotomy. Patients should adopt a sitting position to enhance pulmonary function.

Diagnostic accuracy of subclavian vein versus inferior vena cava collapsibility index for predicting postinduction hypotension: An observational study

Background: Hypotension following induction of general anesthesia (GA) is commonly observed. Ultrasound (US) measurement of collapsibility index (CI) of the inferior vena cava (IVC) for predicting postinduction hypotension has been studied. As there is limited data available comparing the diagnostic accuracy of subclavian vein (SCV) versus IVC-CI, we performed this observational study. Methods: A total of 132 adult patients scheduled for elective surgery under GA were enrolled. US measurements of three readings of maximum and minimum diameters of SCV and IVC were recorded during both quiet and deep breathing, and the mean of three values was calculated. CI was derived using the formula: (dmax – dmin) × 100/dmax. Subsequently, GA was administered using standard technique, irrespective of the findings of SCV and IVC measurements. The administered drugs and dosage were recorded. Hemodynamic parameters were collected at baseline and then at every minute for the first 20 min. The primary objective was to compare the diagnostic accuracies of SCV-CI and IVC-CI for prediction of postinduction hypotension during quiet breathing. The secondary objectives were to compare the diagnostic accuracies during deep breathing and find the correlation between IVC-CI and SC-CI during quiet and deep breathing, incidence of hypotension, and time required to acquire US images. Results: Fifty-seven patients developed postinduction hypotension. During quiet breathing, SCV-CI ≥10% had a sensitivity of 68% and specificity of 56% (area under curve [AUC] [95% confidence interval {CI}] of 0.659 [0.56–0.75]; P = 0.002), while IVC-CI ≥34% had a sensitivity of 70% and specificity of 59% (AUC [95% CI] of 0.672 [0.58–0.76]; P = 0.001) for prediction of postinduction hypotension. During deep breathing, both SCV-CI and IVC-CI had moderate accuracy (P = 0.001 for both). Pearson’s correlation showed a significant positive correlation between SCV-CI and IVC-CI with a correlation coefficient (r) of 0.313 during quiet breathing and 0.379 during deep breathing (P < 0.001). The time required for acquiring US images was significantly less for SCV compared to IVC during both quiet and deep breathing (P < 0.001 for both). Conclusion: Both SCV-CI and IVC-CI were found to have good and comparable diagnostic accuracy for the prediction of postinduction hypotension. We also found a significant positive correlation between SCV-CI and IVC-CI. In comparison to IVC, US scanning of SCV took lesser time to acquire the images.

Differences in Diaphragmatic and Chest Wall Excursion During Quiet Breathing According to Body Position: Dynamic Analysis by MRI

Background and Purpose: The diaphragm is the largest contributor to respiration but is highly influenced by position. Therefore, despite understanding the importance of “positioning” in respiratory physiotherapy, research on diaphragmatic excursion between body positions remains insufficient. This study examined the differences in diaphragm and chest wall excursion between supine, prone, and left and right side-lying positions to investigate the most suitable position for ventilation. Methods: Diaphragmatic excursion, as well as the lateral and anteroposterior diameters of the chest walls of 40 healthy adults (20 males and 20 females), was dynamically imaged during quiet breathing in 4 positions using magnetic resonance imaging, and the amount of excursion was calculated. The Friedman test was used for statistical analysis to compare differences in diaphragmatic and chest wall excursions. Results: The median age was 21.0 years, the median BMI was 20.8 kg/cm2, and all pulmonary function values were normal and within the reference values based on Japanese predicted normal values. The diaphragm and chest wall exhibited significantly greater excursion in the prone position than in other positions (P < .001). In the side-lying position, the anteroposterior diameter excursion of the lower chest wall on the unloaded side was significantly greater (P < .005). However, there was no significant difference between the side-lying and supine positions (P > .05). Conclusions: Diaphragmatic and chest wall excursion during quiet breathing was found to be significantly greater in the prone position than in other positions. This suggests that the prone position is the optimal “positioning” for increased ventilation and may contribute to the prevention of respiratory complications.

Correlation of diaphragmatic mobility and thickening assessed by lung ultrasound with severity of interstitial lung disease.

Studies conducted in interstitial lung disease (ILD) patients to assess diaphragmatic excursion and thickening fraction suggest a weak to strong correlation with pulmonary function parameters. However, diaphragmatic excursion velocity, a novel imaging marker, has not been correlated with pulmonary function and high-resolution computed tomography (HRCT) fibrosis score in ILD patients previously. We conducted a cross-sectional analytical study in 40 ILD patients during quiet (QB) and deep breathing (DB) to measure diaphragmatic thickening, excursion and excursion velocity using transthoracic ultrasound and correlated them with pulmonary function parameters and HRCT fibrosis score. Most diaphragm parameters in DB correlated more strongly with lung function parameters compared to quiet breathing. Right diaphragmatic excursion, during QB and DB, showed positive correlations with forced vital capacity (FVC) z-score (r = 0.591, 0.676) and diffusion capacity of the lung for carbon monoxide (DLCO) z-score (r = 0.437, 0.438), and negative correlations with HRCT fibrosis score (r = -0.439, -0.425), respectively. In addition, right diaphragmatic velocity exhibited positive correlations with FVC z-score (r = 0.388, 0.667) and DLCOz-score (r = 0.139, 0.412), and negative correlations with HRCT fibrosis score (r = -0.454, -0.445). Right diaphragm thickening fraction showed positive correlations with FVC z-score (r = 0.330, 0.460) and DLCOz-score (r = 0.400, 0.426), and negative correlations with HRCT fibrosis score (r = -0.199, -0.237). Similarly, right diaphragmatic thickness indicated positive correlations with FVC z-score (r = 0.526, 0.614) and DLCOz-score (r = 0.298, 0.298), and negative correlations with HRCT fibrosis score (r = -0.398, -0.401). Diaphragmatic excursion velocity during DB showed a weak to moderate correlation with pulmonary function parameters and HRCT fibrosis score and may be utilized as a surrogate marker in ILD patients unable to perform pulmonary function tests or undergo sequential HRCT thorax in follow-up.

Depth-Sensing-Based Algorithm for Chest Morphology Assessment in Children with Cerebral Palsy.

This study introduced a depth-sensing-based approach with robust algorithms for tracking relative morphological changes in the chests of patients undergoing physical therapy. The problem that was addressed was the periodic change in morphological parameters induced by breathing, and since the recording was continuous, the parameters were extracted for the moments of maximum and minimum volumes of the chest (inspiration and expiration moments), and analyzed. The parameters were derived from morphological transverse cross-sections (CSs), which were extracted for the moments of maximal and minimal depth variations, and the reliability of the results was expressed through the coefficient of variation (CV) of the resulting curves. Across all subjects and levels of observed anatomy, the mean CV for CS depth values was smaller than 2%, and the mean CV of the CS area was smaller than 1%. To prove the reproducibility of measurements (extraction of morphological parameters), 10 subjects were recorded in two consecutive sessions with a short interval (2 weeks) where no changes in the monitored parameters were expected and statistical methods show that there was no statistically significant difference between the sessions, which confirms the reproducibility hypothesis. Additionally, based on the representative CSs for inspiration and expirations moments, chest mobility in quiet breathing was examined, and the statistical test showed no difference between the two sessions. The findings justify the proposed algorithm as a valuable tool for evaluating the impact of rehabilitation exercises on chest morphology.

Sex differences in chest electrical impedance tomography findings

Objective. Electrical impedance tomography (EIT) has been used to determine regional lung ventilation distribution in humans for decades, however, the effect of biological sex on the findings has hardly ever been examined. The aim of our study was to determine if the spatial distribution of ventilation assessed by EIT during quiet breathing was influenced by biological sex. Approach. 219 adults with no known acute or chronic lung disease were examined in sitting position with the EIT electrodes placed around the lower chest (6th intercostal space). EIT data were recorded at 33 images/s during quiet breathing for 60 s. Regional tidal impedance variation was calculated in all EIT image pixels and the spatial distribution of the values was determined using the established EIT measures of centre of ventilation in ventrodorsal (CoVvd) and right-to-left direction (CoVrl), the dorsal and right fraction of ventilation, and ventilation defect score. Main results. After exclusion of one subject due to insufficient electrode contact, 218 data sets were analysed (120 men, 98 women) (age: 53 ± 18 vs 50 ± 16 yr (p = 0.2607), body mass index: 26.4 ± 4.0 vs 26.4 ± 6.6 kg m−2 (p = 0.9158), mean ± SD). Highly significant differences in ventilation distribution were identified between men and women between the right and left chest sides (CoVrl: 47.0 ± 2.9 vs 48.8 ± 3.3% of chest diameter (p < 0.0001), right fraction of ventilation: 0.573 ± 0.067 vs 0.539 ± 0.071 (p = 0.0004)) and less significant in the ventrodorsal direction (CoVvd: 55.6 ± 4.2 vs 54.5 ± 3.6% of chest diameter (p = 0.0364), dorsal fraction of ventilation: 0.650 ± 0.121 vs 0.625 ± 0.104 (p = 0.1155)). Ventilation defect score higher than one was found in 42.5% of men but only in 16.6% of women. Significance. Biological sex needs to be considered when EIT findings acquired in upright subjects in a rather caudal examination plane are interpreted. Sex differences in chest anatomy and thoracoabdominal mechanics may explain the results.

Oxygen saturation and work of breathing indices in preterm infants with bronchopulmonary dysplasia compared to healthy preterm infants at discharge.

Thoracoabdominal asynchrony (TAA) is commonly seen in preterm infants. Respiratory inductive plethysmography (RIP) is a noninvasive way to objectively assess work of breathing (WOB) indices. The impact of bronchopulmonary dysplasia (BPD) on TAA at discharge has not been established. The aim of this study is to compare WOB indices in premature infants with a diagnosis of BPD to premature infants without a diagnosis of BPD at discharge. A prospective, observational study of premature infants (<32 weeks gestation) at discharge during quiet breathing in the supine position. RIP noninvasively measured WOB indices. A high-resolution pulse oximeter collected oxygen saturation and heart rate data. This study included thirty-one infants with BPD and thirty-four infants without BPD. Infants diagnosed with BPD had increased phase angle [BPD Φ=73.90 (8.2) vs NoBPD Φ=52.6 (8.2), p = 0.039]. Infants diagnosed with BPD had decreased saturations [BPD SpO2 = 96% (0.4) vs NoBPD Sp02 98% (0.3), p=<0.001], increased time with saturations less than 85% [BPD % =2.74 (0.7) vs NoBPD % =0.91 (0.4), p = .018], and increased time with saturations less than 80% [BPD % =1.57 (0.5) vs NoBPD % =0.52 (0.3), p = 0.045]. There was no difference in heart rate or breaths per minute for infants with BPD versus controls. Premature infants with BPD demonstrated increased TAA and had lower saturations compared to infants without BPD at discharge despite being chronologically older and being discharged at an older corrected gestational age. The impact of BPD on breathing patterns persists at discharge and suggests these patients may have residual lung and/or respiratory muscle dysfunction.

Relationship between changes in the electrical axis of the heart during inspiration and the structural and functional state of the heart according to echocardiography in patients with precapillary pulmonary hypertension

Introduction. A deep breath causes a whole range of physiological effects that are reflected in the electrocardiogram. The purpose of the study is to assess the position of the electrical axis of the heart during deep inspiration compared to quiet breathing in patients with precapillary pulmonary hypertension and compare these data with echocardiographic characteristics of the structural and functional state of the heart. Materials and methods. The study included 40 patients with idiopathic pulmonary hypertension and 40 patients with chronic thromboembolic pulmonary hypertension. Echocardiography assessed the size of the heart chambers, systolic and diastolic function of the right and left ventricles, pulmonary artery pressure, pulmonary vascular resistance and indicators of cardiovascular coupling. Results. The values of the electrical axis of the heart during free breathing were 106° [84°; 123°], on inspiration – 89° [87°; 120°] (p = 0.68). In 50 (62.5 %) patients, during a deep inspiration, the electrical axis of the heart shifted to the left from the original one, and in 30 (37.5 %) patients – to the right. In patients with a displacement of the electrical axis of the heart to the left from the original, compared with the others, the end-diastolic size of the left ventricle, end-diastolic and end-systolic volumes of the left ventricle, stroke volume, cardiac output were statistically significantly lower, and the eccentricity index, pulmonary vascular resistance and effective aortic stiffness – significantly larger. Conclusion. In patients with precapillary pulmonary hypertension, two variants of changes of the heart electrical axis during deep inspiration were identified: a shift to the right from the original and to the left from the original. Patients with a displacement of the electrical axis to the left from the original were characterized by a significantly greater increase in pulmonary vascular resistance, a decrease in left ventricular volumes, stroke volume and cardiac output.

Investigation of the Position and Angle of the Vocal Fold Projected onto the Thyroid Cartilage.

To perform laryngeal framework surgery for unilateral vocal fold paralysis and obtain favorable voice improvement, it is necessary to accurately determine the vocal fold and arytenoid cartilage positions. Thus, the position and angle of the paralyzed vocal folds and arytenoid cartilage projected onto the affected thyroid plate were measured using computed tomography (CT) before and after surgery. Forty-six male patients with thyroid cartilage ossification observed on preoperative CT and vocal fold paralysis were included. Using Adobe Illustrator®, the thyroid plate on the affected side was reconstructed from the continuous images of the sagittal section of the CT examination during participant's quiet breathing (reconstructed affected thyroid plate [RATP]). The anterior commissure mean position was slightly cranial to the midpoint of the thyroid cartilage midline. The paralyzed vocal fold angle was not parallel to the baseline. The average unaffected vocal fold angle during vocalization projected onto the affected thyroid plate was 13.83°, which differed significantly from the average paralyzed vocal fold angle before surgery (19.05°). However, no significant difference was observed in comparison with the average angle of the paralyzed vocal fold after arytenoid adduction. The average distance from the inferior notch of the affected side thyroid cartilage to the affected arytenoid cartilage was 16.7 mm. By understanding the positional relationship between the thyroid cartilage plate and internal structure from preoperative CT images, more effective surgery can be performed according to individual differences. IV Laryngoscope, 134:4088-4094, 2024.

Diagnosis of hemidiaphragm paralysis: refine ultrasound criteria

BackgroundUltrasound has demonstrated its interest in the analysis of diaphragm function in patients with respiratory failure. The criteria used to diagnose hemidiaphragm paralysis are not well defined.MethodsThe aim of this observational retrospective study was to describe the ultrasound findings in 103 patients with diaphragm paralysis, previously diagnosed by conventional methods after various circumstances such as trauma or surgery. The ultrasound study included the recording of excursions of both diaphragmatic domes and the measurement of inspiratory thickening.ResultsOn paralyzed hemidiaphragm, thickening was less than 20% in all patients during deep inspiration. Thinning was recorded in 53% of cases. In some cases, the recording of the thickening could be difficult. The study of motion during voluntary sniffing reported a paradoxical excursion in all but one patient. During quiet breathing, an absence of movement or a paradoxical displacement was observed. During deep inspiration, a paradoxical motion at the beginning of inspiration followed by a reestablishment of movement in the cranio-caudal direction was seen in 82% of cases. In some patients, there was a lack of movement followed, after an average delay of 0.4 s, by a cranio-caudal excursion. Finally, in 4 patients no displacement was recorded. Evidence of hyperactivity (increased inspiratory thickening and excursion) of contralateral non-paralyzed hemidiaphragm was observed.ConclusionTo accurately detect hemidiaphragm paralysis, it would be interesting to combine the ultrasound study of diaphragm excursion and thickening. The different profiles reported by our study must be known to avoid misinterpretation.

Exhaled breath analysis in adult patients with cystic fibrosis by real-time proton mass spectrometry

BackgroundProton-transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) is a promising tool for a rapid online determination of exhaled volatile organic compounds (eVOCs) profiles in patients with cystic fibrosis (CF). ObjectiveTo detect VOC breath signatures specific to adult patients with CF compared with controls using PTR-TOF-MS. Methods102 CF patients (54 M/48, mean age 25.6 ± 7.8 yrs) and 97 healthy controls (56 M/41F, mean age 25.8 ± 6.0 yrs) were examined. Samples from normal quiet breathing and forced expiratory maneuvers were analyzed with PTR-TOF-MS (Ionicon, Austria) to obtain VOC profiles listed as ions at various mass-to-charge ratios (m/z). ResultsPTR-TOF-MS analysis was able to detect 167 features in exhaled breath from CF patients and healthy controls. According to cluster analysis and LASSO regression, patients with CF and controls were separated. The most significant VOCs for CF were indole, phenol, dimethyl sulfide, and not indicated: m/z = 297.0720 ([C12H13N2O7 and C17H13O5]H + ), m/z = 281.0534 ([C19H7NO2, C12H11NO7 and C16H9O5]H + ) during five-fold cross-validation both in forced expiratory maneuver and in normal quiet breathing. ConclusionPTR-TOF-MS is a promising method for determining the molecular composition of exhaled air specific to CF.

Breath-by-breath Analysis of a Rat Model of Pompe Disease Exposes Deficits in High-frequency Behaviors

Pompe disease (PD) is caused by a loss of function of the enzyme acid-α-glucosidase (GAA) leading to glycogen accumulation, neuromuscular dysfunction, and breathing failure. Here, we characterized longitudinal changes in breathing of GAA null ( Gaa−/−) rats on a breath-by-breath basis using a novel respiratory event detection algorithm. Adult Pompe (n = 5) and Sprague Dawley (n = 5) rats were implanted with chronic diaphragm EMG electrodes. Once a month from 4-10 months of age, full body plethysmography with concurrent EMG was used to record respiratory waveforms under room air and hypoxia. Waveforms were analyzed by the Adjustable Baselines Respiratory Analysis Program (ABRAP) algorithm. An adaptive threshold identified “respiratory events” defined as crossings of a threshold set between the recent maxima and minima of the waveform. After event identification, a range of waveform characteristics are calculated and tagged to that event. Averages of each characteristic were taken for all events and then analyzed based on respiratory rate in breaths/minute (bpm): low (&lt;120 bpm, ‘quiet breathing’), medium (between 120 and 240 bpm) and high (&gt;240 bpm, ‘high frequency sniffng’). In room air, Pompe rats had a lower breathing rate than wildtype rats by month 10 (173 vs 285 bpm, standard error of the difference (SE of diff.) 37, p=0.03). This decrease in frequency was driven by the high rate events as there were no differences in the mean rate of low rate events at month 10 (80 vs 83 bpm, SE of diff. 3) while the frequency of high rate events was significantly lower by 9 months (mo 9: 393 vs 440 bpm, SE of diff. 16, p=0.04, mo 10: 383 vs 440 bpm, SE of diff. 17, p=0.008). Not only was the breathing frequency of high-rate events impaired in Pompe rats, but there was a trend towards decrease in the proportion of events falling in the high rate category indicating less time spent in high rate breathing behaviors (mo 4: 52 vs 59%, SE of diff. 6, mo 10: 25 vs 52%, SE of diff. 9) with a concomitant increase in the proportion of low frequency events. Additionally, there was a main effect of genotype on the latency between diaphragm activation and onset of inspiratory flow during hypoxia with Pompe rats having a longer latency across all months and frequency bands. This difference was most pronounced in the medium (44 vs 29 ms, SE of diff. 4 ms, p=0.003) frequency events. Active expiration was impaired in Pompe animals with peak post-event airflow (maximum positive pressure reached before the next inspiratory effort) blunted across all months. This effect was pronounced in the high frequency events (0.16 mL vs 0.24 mL, SE of diff. 0.01, p=0.0001). These deficits in high frequency events are consistent with progressive neuromuscular diaphragm weakness. We conclude that comprehensive analyses of all respiratory events over extended recording periods enables detection of altered breathing behaviors that may be missed when assessing only short periods of quiet breathing. In turn, this may help uncover a respiratory signature of disease progression in Pompe disease or other neuromuscular conditions. 2R01HD052682-11A1 (DDF, BJB), T32HL134621 (AM), R01HL153102 (ED), SPARC OT2OD023854 (ED), Craig H. Neilsen Pilot Grant (ED). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

“Open Your Mouth and Stick out Your Tongue:” Revisiting Static and Dynamic Maneuvers in Head and Neck CT

The head and neck region has a complex anatomy, making assessing lesion extension challenging. Current CT technology has not been able to overcome these challenges. Both static and dynamic maneuvers have been developed to better evaluate some areas where mucosal apposition prevents appropriate lesion characterization. Static maneuvers do not require modification of the breathing pattern and can be performed during quiet breathing acquisition. Dynamic maneuvers require an extra acquisition, with increased radiation exposure; thus, patients and scanning areas should be carefully selected. The purpose of this article is to describe these maneuvers, how to perform them, and their clinical application.Learning Objective: To describe useful dynamic and static maneuvers in head and neck diagnostic imaging and recognize the structures that may be better assessed by performing them

Relationship Between Diaphragm Thickness, Thickening Fraction, Dome Excursion, and Respiratory Pressures in Healthy Subjects: An Ultrasound Study

PurposeDiaphragm ultrasonography is used to identify causes of diaphragm dysfunction. However, its correlation with pulmonary function tests, including maximal inspiratory (MIP) and expiratory pressures (MEP), remains unclear. This study investigated this relationship by measuring diaphragm thickness, thickening fraction (TF), and excursion (DE) using ultrasonography, and their relationship to MIP and MEP. It also examined the influence of age, sex, height, and BMI on these measures.MethodsWe recruited healthy Japanese volunteers and conducted pulmonary function tests and diaphragm ultrasonography in a seated position. Diaphragm ultrasonography was performed during quiet breathing (QB) and deep breathing (DB) to measure the diaphragm thickness, TF, and DE. A multivariate analysis was conducted, adjusting for age, sex, height, and BMI.ResultsBetween March 2022 and January 2023, 109 individuals (56 males) were included from three facilities. The mean (standard deviation) MIP and MEP [cmH2O] were 72.2 (24.6) and 96.9 (35.8), respectively. Thickness [mm] at the end of expiration was 1.7 (0.4), TF [%] was 50.0 (25.9) during QB and 110.7 (44.3) during DB, and DE [cm] was 1.7 (0.6) during QB and 4.4 (1.4) during DB. Multivariate analysis revealed that only DE (DB) had a statistically significant relationship with MIP and MEP (p = 0.021, p = 0.008). Sex, age, and BMI had a statistically significant influence on relationships between DE (DB) and MIP (p = 0.008, 0.048, and < 0.001, respectively).ConclusionIn healthy adults, DE (DB) has a relationship with MIP and MEP. Sex, age, and BMI, but not height, are influencing factors on this relationship.

The Clinical Investigation on Varicocele and Sperm Quality in the Tibet an Plateau of China: A Prospectively Planned Retrospective Cohort Study.

Varicoceles are a common cause of male infertility, affecting up to 35% of men undergoing fertility evaluations. This study aims to investigate the potential influence of altitude and residence time on the occurrence of varicoceles, as well as on sperm quality and sterility in plateau areas. A total of 168 patients with varicocele were enrolled in the study, and the study population was divided into groups based on their direct exposure to different high altitudes due to their living locations. The internal diameter in Quiet breath (Dr), internal diameter in Valsalva maneuver (Dv), reflux peak value, and reflux time are gradually increased accompanied with altitude elevation and residence time extension. The number of cases above 4,500 m also increased with the severity of varicocele, and the altitude of clinical types was higher than that of subclinical types of varicocele. Especially above 4,500 m, the Dv, Dr, reflux peak value, and reflux time all increased with the severity of varicocele. The severity of varicocele was positively correlated with the residence time in plateau area. Patients with residence time of more than 1 year had higher values of Dr, Dv, differentiation time, reflux peak value, and reflux time than those with residence time of less than 1 year. Compared to 3,650 m, patients with varicocele in 4,500 m also have worse semen quality. Both altitude and residence time are strongly positively related to the severity and incidence rate of varicocele in plateau areas.

Indices of airway resistance and reactance from impulse oscillometry correlate with aerosol particle emission in different age groups

Airborne transmission of pathogens plays a major role in the spread of infectious diseases. Aerosol particle production from the lung is thought to occur in the peripheral airways. In the present study we investigated eighty lung-healthy subjects of two age groups (20–39, 60–76 years) at rest and during exercise whether lung function parameters indicative of peripheral airway function were correlated with individual differences in aerosol particle emission. Lung function comprised spirometry and impulse oscillometry during quiet breathing and an expiratory vital capacity manoeuvre, using resistance (R5) and reactance at 5 Hz (X5) as indicators potentially related to peripheral airway function. The association between emission at different ventilation rates relative to maximum ventilation and lung function was assessed by regression analysis. In multiple regression analyses including age group, only vital capacity manoeuvre R5 at 15% to 50% of end-expiratory vital capacity as well as quiet breathing X5 were independently linked to particle emission at 20% to 50% of maximum ventilation, in addition to age group. The fact that age as predictive factor was still significant, although to a lower degree, points towards further effects of age, potentially involving surface properties not accounted for by impulse oscillometry parameters.

Graded onset of parasternal intercostal inspiratory activity detected with surface electromyography in healthy young females and males.

Intramuscular recordings of single motor unit activity from parasternal intercostal muscles show a rostrocaudal gradient in timing and amplitude of inspiratory activity. This study determined the feasibility of surface electromyographic activity (EMG) to measure graded parasternal intercostal activity in young females and males during quiet breathing and breathing with inspiratory resistive loads. Surface EMGs were recorded from the 1st-to-5th parasternal intercostal muscles during 10 min of breathing. EMGs were processed to remove 50 Hz and electrocardiogram artifacts and integrated. Amplitude and onset time of inspiratory activity were measured from waveform averages triggered at the onset of inspiratory flow. Onset times were measured independently by two assessors, blinded to interspace and EMG scale, with excellent agreement (ICC3,k = 0.86). The onset of inspiratory activity in the 1st-to-3rd interspaces was at or within ∼400 ms of the start of inspiratory airflow, but activity in the caudal (4th and 5th) spaces was delayed by up to ∼1,000 ms (P < 0.001). There was no main effect of sex on onset time (P = 0.07), but an interaction with interspace (P < 0.001) revealed that inspiratory activity in the caudal interspaces was delayed by 15% of inspiratory time in female participants compared with 30% of inspiratory time in male participants. Inspiratory loads did not affect EMG onset time (P = 0.31). Thus, surface EMG is feasible to assess the onset time of inspiratory activity as a marker of inspiratory neural drive and pattern of activation across spaces, in both females and males.NEW & NOTEWORTHY We demonstrated that surface EMG is a valid method to measure graded inspiratory EMG in the parasternal intercostal muscles in healthy young male and female participants during quiet breathing and loaded breathing. Across the 1st-to-5th interspaces, there was more homogenous activation in women and more graded activity in men across parasternal intercostal muscles during breathing. By recording surface EMG from both male and female participants, we have revealed sex differences in inspiratory activity across intercostal muscles.

Breathing and Speech Adaptation: Do Speakers Adapt Toward a Confederate Talking Under Physical Effort?

This study investigated whether speakers adapt their breathing and speech (fundamental frequency [fo]) to a prerecorded confederate who is sitting or moving under different levels of physical effort and who is either speaking or not. Following Paccalin and Jeannerod (2000), we would expect breathing rate to change in the direction of the confederate's, even if the participant is physically inactive. This might in turn affect their speech acoustics. We recorded the speech and respiration of 22 native German speakers. They produced solo and synchronous read speech in interaction with a confederate who appeared on a prerecorded video. There were three within-subject experimental conditions: the confederate (a) sitting, (b) biking with light effort, or (c) biking with heavier effort. During speech, the confederate's inhalation amplitude and fo increased with physical effort, as expected. Her breath cycle duration changed differently, probably because of read speech constraints. Overall, the only adaptation the participants showed was higher fo with increase in the confederate's physical effort during synchronous, but not solo, speech. Additionally, they produced shallower inhalations when observing the confederate biking in silence, as compared to the condition without movement. Crucially, the participants' acoustic and breathing data showed large interindividual variability. Our findings indicate that, in this paradigm, convergence only took place on fo during synchronous speech and that this phonetic adaptation happened independently from any speech breathing adaptation. It also suggests that participants may adapt their quiet breathing while watching a person performing physical exercise but that the mechanism is more complex than that explained previously.

Distribution of regional lung function in upright healthy subjects determined by electrical impedance tomography in two chest examination planes.

Objective. The variation in pulmonary gas content induced by ventilation is not uniformly distributed in the lungs. The aim of our study was to characterize the differences in spatial distribution of ventilation in two transverse sections of the chest using electrical impedance tomography (EIT).Approach. Twenty adult never-smokers, 10 women and 10 men (mean age ± SD, 31 ± 9 years), were examined in a sitting position with the EIT electrodes placed consecutively in a caudal (6th intercostal space) and a cranial (4th intercostal space) chest location. EIT data were acquired during quiet breathing, slow and forced full expiration manoeuvres. Impedance variations representing tidal volume (VT), vital capacity (VC), forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were calculated at the level of individual image pixels and their spatial distribution was determined using the following EIT measures: the centres of ventilation in ventrodorsal (CoVvd) and right-to-left direction (CoVrl), the dorsal and right fractions of ventilation, the coefficient of variation (CV) and the global inhomogeneity (GI) index.Main results. The sums of pixel ventilation-related impedance variations reproduced reliably the volumetric dissimilarities amongVT, VC, FEV1and FVC, with no significant differences noted between the two examination planes. Significant differences in ventilation distribution were found between the planes during tidal breathing and slow full expiration, mainly regarding the ventrodorsal direction, with higher values of CoVvdand dorsal fraction of ventilation in the caudal plane (p< 0.01). No significant differences in the spatial distribution of FEV1and FVC were detected between the examination planes.Significance. The spatial distribution of ventilation differed between the two examination planes only during the relaxed (quiet breathing and slow VC manoeuvre) but not during the forced ventilation. This effect is attributable to the differences in thoracoabdominal mechanics between these types of ventilation.

가로막 이완기법이 가로막 움직임과 폐활량에 미치는 영향

Purpose: The purpose of this study was to investigate the immediate effect of diaphragm release technique applied to healthy adults on diaphragmatic mobility and slow vital capacity.&#x0D; Methods: This study included 21 healthy participants (13 males and 8 females). The participants performed exercises 10 times in 1 set diaphragm release technique, with a total of 3 sets. Before and after the intervention of the diaphragm release technique, diaphragmatic mobility was assessed using ultrasound, and slow vital capacity was evaluated using a portable digital spirometry device.&#x0D; Results: After the diaphragm release technique intervention, diaphragmatic mobility significantly increased in quiet breathing and deep breathing. In the case of slow vital capacity, only vital capacity increased significantly.&#x0D; Conclusion: Diaphragmatic mobility and slow vital capacity were affected by the diaphragm release technique, and it is believed that the diaphragm release technique will be useful as an intervention method in order to improve respiratory function.